Economizer pressure regulating system

ABSTRACT

The economizer pressure regulator installed in the line from the vapor area of the economizer to the second stage of the centrifugal compressor in a refrigeration system includes a valve movable to open and close a port in the line. The valve is movable toward open position by the direct application of pressure from the economizer against one side of the valve. The valve is urged toward closed position by a spring acting against the opposite side of the valve. The valve is also urged toward closed position by the pressure in the cooler of the refrigeration system. Accordingly, the vapor area of the economizer is not connected to the second stage of the compressor until the pressure in the economizer exceeds the pressure in the cooler, and, in addition, the force of the spring acting on the valve.

Untte w Kersehbanmer et al.

Aug. 6, 1974 ECONOMIZER PRESSURE REGULATING SYSTEM inventors: Hans Gerhard Kersehbaumer;

James W. Endress, both of Syracuse, NY.

Assignee: Carrier Corporation, Syracuse, NY.

Filed: July 23, 1973 Appl. No.: 381,811

U8. (El. 62/196, 62/217, 62/510 Int. Cl. F25!) 41/00 Field at Search 62/196, 510, 217

References Cited UNITED STATES PATENTS Primary Examiner-Meyer Perlin Attorney, Agent, or Firm-J. Raymond Curtin [57] ABSTRACT The economizer pressure regulator installed in the line from the vapor area of the economizer to the second stage of the centrifugal compressor in a refrigeration system includes a valve movable to open and close a port in the line. The valve is movable toward open position by the direct application of pressure from the economizer against one side of the valve. The valve is urged toward closed position by a spring acting against the opposite side of the valve. The valve is also urged toward closed position by the pressure in the cooler of the refrigeration system. Accordingly, the vapor area of the economizer is not connected to the second stage of the compressor until the pressure in the economizer exceeds the pressure in the cooler, and, in addition, the force of the spring acting on the valve.

1 Claim, 2 Drawing lFigures PATENTED RUB 6 74 SHEET 1 OF 2 PMENTEDAUG 8|974 SHEEF E OF 2 ECONOMIZER PRESSURE REGULATING SYSTEM BACKGROUND OF THE INVENTION During the startup of a two-stage centrifugal compressor in a refrigeration system having closed guide vanes before the first stage of the compressor and no guide vanes before the second stage, the interstage pressure can be as low as, or lower than, the first stage pressure. That is, the pressure in the economizer can be as low as, or lower than, the pressure in the cooler. Accordingly, there is no pressure difference available to force the liquid refrigerant from the economizer to the cooler.

At present, that problem is attended to by a butterfly valve installed in the passage from the economizer to the compressor. The valve is operated by a driver mounted externally of the passage, as a bellows or pis ton arrangement, which is actuated by pressure differential between the economizer and the cooler. With economizer pressure lower than the pressure in the cooler, the valve is closed. Such an arrangement involves many moving parts requiring maintenance, and also a source of operating power may be required.

This invention has as an object an economizer pressure regulator embodying a self-contained structure having only one moving part, and is operable without any application of power from an external source.

SUMMARY OF THE INVENTION The open ends of a casing are connected in the suction passage extending from the economizer to the intake of the second stage of the centrifugal compressor. A cylinder is disposed axially in the casing and forms, in conjunction with the casing, a flow area extending lengthwise through the casing and forming part of the suction flow passage. The cylinder is formed with an open end confronting the flow from the economizer, the opposite end of the cylinder is closed. A port, in proximity to the open end of the cylinder, provides communication between the flow from the economizer to the flow area in the casing. A valve is mounted for reciprocation in the cylinder and is urged in position to uncover the port by the pressure in the economizer against one side of the valve. The valve is urged toward closed position by pressure in the cooler applied through a control line to the opposite end of the piston, and in addition, by force exerted by a spring. Accordingly, the suction flow passage from the economizer to the compressor is closed, unless the pressure in the economizer exceeds the pressure in the cooler by an amount equivalent to the force exerted by the spring on the valve. A two position valve is operable to close off the control line and apply economizer pressure to the opposite end of the valve. The spring then maintains the balance valve in port closing position.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of a refrigeration system wherein the economizer pressure regulator of our invention is employed; and

FIG. 2 is a lengthwise sectional view of the pressure regulator.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. I, the refrigeration system shown therein includes a cooler 10. A suction passage 12 containing conventional inlet guide vanes 13 extends from the vapor area of the cooler 10 to "the intake of the first stage l5 of the two-stage centrifugal compressor 17. The refrigerant is discharged from the second stage 19 of the compressor through line 2i to the condenser 22. The condenser is formed with a sump 23 connected by a refrigerant flow line to cooler 10.

Usually, in systems of the type disclosed herein, the refrigerant flow line to the cooler includes an economizer. The vapor area of the economizer is connected by a suction line flow passage to the second stage of the compressor. This arrangement effects a reduction of the pressure in the economizer to cause part of the refrigerant therein to flash, thereby reducing the temperature of the remainder of the refrigerant flowing to the cooler.

As shown in FIG. 1, a refrigerant flow line consists of a section 25 extending from the sump 23 to the economizer 26. A second refrigerant flow line section 28 extends from the economizer to the lower section of the cooler 10. A float control metering valve 3% is mounted in the sump 23 and a similar valve 31 is mounted in the economizer. The refrigerant vapor flow means from the vapor area 33 of the economizer 26 to the second stage of the compressor 17 includes a conduit section 35 connected to one end of the pressure regulator 37. The opposite end of the regulator is connected by a second conduit section 40 extending to the inlet of the second stage 19 of the compressor 17.

Referring to FIG. 2, the conduit section 35 is welded to a pipe flange 41. The conduit. section 40 is welded to a similar flange 42. A flange 48 is connected to the flange 411 as by bolts 45. A tubular casing 4W is welded at one end to the flange M, and the opposite end of the casing is welded to a flange d9 which is connected to the flange 42 as by bolts 50. It will be seen the flange 43 is formed with a portion 51 extending inwardly from the casing 47. A cylinder 53 is fixedly secured to the flange portion 51. The cylinder is disposed axially within the casing 47, and in spaced relation thereto, forming a flow area 55 between the cylinder and the casing. The end of the cylinder confronting the flange 43 is open, and the opposite end of the cylinder is provided with a closure 57.

A piston valve is mounted for reciprocation in the cylinder 53 and is movable toward and from the flange section 51 to open and close a port oil located in proximity to the open end of the cylinder. The piston valve is provided with sealing rings 62. The port 61 is conveniently formed, as shown in FIG. 2, by terminating the open end of the cylinder 53 in axial spaced relation to the flange Sll. With this arrangement, the cylinder 53 is fixed to support members 63 which are in turn fixed to the flange section 51. With this construction, a spacer member 65 is positioned within the bore 67 of the inner portion 51 of flange 43. A valve packing or seat 70 is positioned on the spacer 65 and a packing 71 is interposed between the spacer 65 and the flange 41. The valve 60 is formed with a discoidal portion 73. A helical compression spring 75 is interposed between the portion 73 of the piston and the cylinder closure 57. A stop member 77 is fixed to the cylinder closure 57 and serves to limit movement of the valve 60 in a direction away from the valve seat 70.

It will be apparent that the valve 60 is moved in a direction away from the seat 70, to open the port 61, by

the pressure in the economizer being applied against the valve. This movement is opposed by the spring 75. It is also opposed by the pressure in the cooler which is conducted through sections 89, 81 connected by a two position valve 82 to the area of the cylinder 53 intermediate the valve and the cylinder closure 57. With the valve 60 moved upwardly to uncover the port 61, the flow passage is continuous through the conduit section 35, through the flow area 55, to the conduit section 40 extending to the compressor. It will be seen that in order for the valve 60 to be moved to open the port 61, the pressure in the economizer, applied to the valve through the section 35, must be in excess of the pressure applied against the opposite side of the valve 88 through the control line sections 80, 81 and valve 82 in the position shown in FIG. 1. In addition, the pressure in 35 must be such as to overcome the force exerted by spring 75 on the piston valve.

In refrigeration systems operating at above atmospheric pressure, a storage tank for the refrigerant is required. During prolonged periods of shutdown or for servicing the components of the system, the refrigerant is transferred into the storage tank which is isolated from the rest of the system. Referring to FIG. 1, the line section 25 is provided with a shut off valve 90 and a similar valve 91 is connected in the section 28. With the valve 91 closed, the compressor is operated to transfer the refrigerant into the economizer 26 which is dimensioned to provide a storage tank of proper capacity. The economizer is then isolated from the system by closing the valve 90 and by rotating the valve 82 in a clockwise direction to connect the control section 80 to a branch line 53 extending to the flow section 35.

it will be noted the pressure regulator embodies a self-contained structure having only one moving part and requiring no external power for its operation.

While we have described the preferred embodiment of our invention, it is to be understood that the invention is not limited thereto, but may be otherwise embodied within the scope of the following claims.

We claim:

1. In a refrigeration machine including a compressor,

a condenser, a cooler connected to form a closed circuit for the flow of refrigerant, an economizer interposed in the circuit between the condenser and cooler for receiving liquid refrigerant from the condenser and forwarding same to the cooler, and a line connecting the economizer with the compressor intermediate the suction and discharge thereof whereby a portion of the liquid refrigerant in the economizer is vaporized and flows to the compressor,

i. refrigerant flow control means regulating flow of refrigerant in said line including,

ii. cylinder means,

iii. piston valve means having a first surface subject to economizer pressure arranged in said cylinder regulating flow from the economizer to the compressor,

iv. means applying a force to the opposite surface of the piston,

v. control means for selectively imposing cooler pressure and economizer pressure against the opposite surface of said piston valve means. 

1. In a refrigeration machine including a compressor, a condenser, a cooler connected to form a closed circuit for the flow of refrigerant, an economizer interposed in the circuit between the condenser and cooler for receiving liquid refrigerant from the condenser and forwarding same to the cooler, and a line connecting the economizer with the compressor intermediate the suction and discharge thereof whereby a portion of the liquid refrigerant in the economizer is vaporized and flows to the compressor, i. refrigerant flow control means regulating flow of refrigerant in said line including, ii. cylinder means, iii. piston valve means having a first surface subject to economizer pressure arranged in said cylinder regulating flow from the economizer to the compressor, iv. means applying a force to the opposite surface of the piston, v. control means for selectively imposing cooler pressure and economizer pressure against the opposite surface of said piston valve means. 